Gait variability is more strongly associated with walking speed than with age

Based on a complex systems perspective, quantifying the structure of gait variability using nonlinear analysis techniques have been posited to be sensitive to age-related declines in the biological subsystems. This study tested this claim by investigating relationships between age and various measures of gait across the adult lifespan.

Thirty-four adults ranging from 23 to 71 years old completed a 6-minute walk at their preferred speed. Seventeen measures of gait were quantified, including mean spatiotemporal measures of gait and linear and nonlinear measures of gait variability.

Contrary to expectation, older age was positively correlated (p values <.05) only with coefficient of variation of stride length and sample entropy of stride time (R²s = .12 and.15, respectively). Age was instead most strongly associated (p < .05) with slower preferred gait speed (R² =.23). Compared to age, gait variability measures were more strongly associated with preferred gait speed. Slower walking was associated (p values <.05) with increased coefficient of variation of stride length (R² =.34), sample entropy of stride length (R² =.14), the correlation dimension of knee motion and vertical pelvis motion (R² =.34 and R² =.26, respectively), and decreased sample entropy of stride time (R² =.51) and dynamic stability of mediolateral pelvis motion (R² =.11).

These findings emphasize that measures of gait variability may not be particularly sensitive to the age-related declines in the biological subsystems but rather, are more predictive of preferred walking speed.